With the development of the mobile communication technology, it becomes a characteristic service content of the intelligent mobile phone of the 3rd-generation (3G) mobile communication technology to realize the videophone in mobile terminals, such as mobile phones from a variety of low-end mobile phones. Through the videophone, the face-to-face real-time communication of people can be realized, namely: the both parties of the call can see each other during the call. The videophone has been widely applied to many aspects, such as teleconference, distance teaching, telemedicine and is the like in recent years, and the videophone comprises two-party call, three-party call and the like, wherein the three-party call is also known as conference call in which the third party call can be accessed without interrupting the existing call of the two parties, so as to further realize multi-party call with each other.
However, in the present videophone application of the mobile terminal, the three-party call cannot be implemented due to the limitations of the 3G network bandwidth. Specifically speaking, the bandwidth allocation mechanism of the 3G network is very similar to the wireless router, whose theoretical downlink speed is up to 3-4 Mbit/s, and the theoretical uplink speed is up to about 2 Mbit/s, however in the practical application, in addition to allocating certain channels to the wireless Internet users to use, the base station has to allocate certain channels to the voice communication users to use, that is to say, the channel resources of the 3G network are not shared by each user individually, but are shared by multiple users. Therefore, in the practical application, the access speed of the 3G network not only depends on the signal strength of the base station, but also depends on the current communication traffic of the base station; if the base station is very idle, the access speed is very fast, on the contrary, the access speed is very slow.
In such a case, to implement the three-party call in the videophone application of the mobile terminal will greatly increase the consumption of the network bandwidth, even when the network bandwidth is smaller than a certain value, the three-party call cannot be established, thereby the user experience is greatly affected. Therefore, how to use the limited bandwidth to implement the three-party call in the videophone application of the mobile terminal becomes an important technical content in the research and development of the 3G intelligent mobile phone.